A breathing question

[Owlsman]

No, not for me! My '62 4 x door has the breather set up as per the pic of my engine bay.

For the lack of something better to do, I smartened up the air filter box the other day, by stripping and respraying it. During the old paint removal, I noticed that the pipe/tube on the bottom plate of the air filter that connects to the rocker cover outlet via the short hose, was completely blocked up with paint. It took a while but I unblocked it eventually.

I'll freely admit that I don't understand how or why an engine 'breathes' but presumably, with the rocker cover hose effectively completely blocked off, it would be like me trying to inhale and exhale through a blocked nose. The car has been running well for some time but when I had a quick tootle round the block today, it did seem to be running particularly sweetly. It could be my imagination but would unblocking the hole in the air filter box make any perceptible difference to the way the engine runs? Also, why is it such a small hole anyway? Why not a simple open-ended pipe like on the rocker cover?

If possible, a short idiot's guide to engine breathing would be appreciated please. Thanks in advance.

[svenedin]

What a very tidy engine bay. I notice you have the heater pipe on the manifold side. This is non-standard but means the thermostat can be changed without having to remove the pipe. There’s also a Hardi fuel pump pretending to be an SU with an SU sticker!

No engine has piston rings that make a perfect seal in the cylinder bore. This means that some of the gases from the combustion explosion get past the piston rings into the crankcase. This is called “blow-by”. One of the products of combustion is steam. Water is a bad thing to have in the oil. If there was no breathing system there would be “crankcase compression” (too much pressure in the crankcase) and the engine would tend to leak oil through the gaskets. The engine breathing system aims to relieve the crankcase compression and the oily fumes are fed into the inlet system and burnt in the engine.

Symptoms of a blocked breather system include oil leaks and “mayonnaise” (an emulsion of oil and water) in the rocker cover
Stephen

[Grumpy21]

You may also find, as I did, that sorting out the breather system reduces or even eliminates oil leaks you may have.

My traveller left a trail of oil not unlike the Torrey Canyon did in the 60s until the breather was sorted out.

[svenedin]

You may also find, as I did, that sorting out the breather system reduces or even eliminates oil leaks you may have.

My traveller left a trail of oil not unlike the Torrey Canyon did in the 60s until the breather was sorted out.

Mine too!

[King Kenny]

My Traveller was the same until I unblocked the rubber breather tube. I could not believe the amount of gunk that a small tube could hold. I swear the car ran sweeter afterword too. Beautiful engine by the way.

[philthehill]

The heater return pipe over the manifold is standard. Part No: ACA5514 (MOSS).
There were other variations to the heater return pipe including one that went over the top of the thermostat housing as stated above.

[Bill_qaz]

What a very tidy engine bay. I notice you have the heater pipe on the manifold side. This is non-standard but means the thermostat can be changed without having to remove the pipe. There’s also a Hardi fuel pump pretending to be an SU with an SU sticker!

No engine has piston rings that make a perfect seal in the cylinder bore. This means that some of the gases from the combustion explosion get past the piston rings into the crankcase. This is called “blow-by”. One of the products of combustion is steam. Water is a bad thing to have in the oil. If there was no breathing system there would be “crankcase compression” (too much pressure in the crankcase) and the engine would tend to leak oil through the gaskets. The engine breathing system aims to relieve the crankcase compression and the oily fumes are fed into the inlet system and burnt in the engine.

Symptoms of a blocked breather system include oil leaks and “mayonnaise” (an emulsion of oil and water) in the rocker cover
Stephen

Mine is same 1962 and the heater pipe runs the same, why do you think it's none standard?

The pipe from the air filter let's air into the rocker cover and the crankcase breathes out of the pipe on exhaust side of engine and I believe you should have a none vented oil cap.
You pipe is infront of your carburettor so the air intake is by the exhaust manifold for winter. You can pivot to point forward for summer use.

20230622_155213.jpg (2.21 MiB) Viewed 2332 times

[myoldjalopy]

I prefer the older arrangement where the heater hose runs from the bottom of the rad along the engine bay floor and up into the bulkhead. Not in the way of anything

[svenedin]

The heater return pipe over the manifold is standard. Part No: ACA5514 (MOSS).
There were other variations to the heater return pipe including one that went over the top of the thermostat housing as stated above.

Fair enough. I’ve never seen the heater pipe on the manifold side, only on the other side. With my engine and manifold the pipe could not be routed on the manifold side. Incidentally, how is the heater warning plate held to the pipe?

IMG_9121.jpeg (2.52 MiB) Viewed 2323 times

[Bill_qaz]

What a very tidy engine bay. I notice you have the heater pipe on the manifold side. This is non-standard but means the thermostat can be changed without having to remove the pipe. There’s also a Hardi fuel pump pretending to be an SU with an SU sticker!

No engine has piston rings that make a perfect seal in the cylinder bore. This means that some of the gases from the combustion explosion get past the piston rings into the crankcase. This is called “blow-by”. One of the products of combustion is steam. Water is a bad thing to have in the oil. If there was no breathing system there would be “crankcase compression” (too much pressure in the crankcase) and the engine would tend to leak oil through the gaskets. The engine breathing system aims to relieve the crankcase compression and the oily fumes are fed into the inlet system and burnt in the engine.

Symptoms of a blocked breather system include oil leaks and “mayonnaise” (an emulsion of oil and water) in the rocker cover
Stephen

Mine is same 1962 and the heater pipe runs the same, why do you think it's none standard?

The pipe from the air filter let's air into the rocker cover and the crankcase breathes out of the pipe on exhaust side of engine and I believe you should have a none vented oil cap.The fumes are not drawn into the air intake.
You pipe is infront of your carburettor so the air intake is by the exhaust manifold for winter. You can pivot to point forward for summer use.
20230622_155213.jpg

[Bill_qaz]

Stephen what is a heater warning plate?

[Owlsman]

Thanks all, for your responses. I'm breathing a lot easier now.......as is the car!!

Why is the hole so small on the air filter base plate though, if as seems likely, it can easily get blocked up?

My engine does drip a bit of oil but I wouldn't say excessively so. I'll have to put a clean piece of cardboard on the garage floor and see if there is any difference, post unblocked breather!

Re the summer/winter settings for the air filter box - do I simply turn it a full 180°?

Well spotted, Stephen - the fuel pump is indeed an electronic jobbie but identifying as something quite different. Nowadays all the rage and quite acceptable in some circles, I hear!

The 'Caution' warning plate is held on the copper section of the heater pipe by 2 spring clips riveted through the plate.

Thanks again for all your replies.

[svenedin]

Stephen what is a heater warning plate?

It’s a metal plate that cautions that the heater cannot be completely drained and that antifreeze should used. It’s just an original detail I would like to have.

[Bill_qaz]

Thanks all, for your responses. I'm breathing a lot easier now.......as is the car!!





Re the summer/winter settings for the air filter box - do I simply turn it a full 180°?
. [/quote
If you zoom in you can see the inlet is just under the float bowl of the carburettor so not quite 180 degrees

20230801_153346.jpg (1.7 MiB) Viewed 2292 times

]

[Bill_qaz]

Stephen what is a heater warning plate?

It’s a metal plate that cautions that the heater cannot be completely drained and that antifreeze should used. It’s just an original detail I would like to have.

Ah I get it now, the warning sign
https://www.morrisminorspares.com/cooli ... ge-p829607

[rocco]

Stephen what is a heater warning plate?

You can see it on my engine here. I took the photo on collection day so no comments about cleanliness are necessary!

MoggyEngineHeaterWarning.jpg (909.01 KiB) Viewed 2274 times

[svenedin]

Stephen what is a heater warning plate?

You can see it on my engine here. I took the photo on collection day so no comments about cleanliness are necessary!

MoggyEngineHeaterWarning.jpg

Thank you. Does the warning sign/plate/badge have a backing plate or are the clips riveted directly to the badge? Terry clips and a badge are easy enough to buy but if there’s a backing plate that would be tricky to find although not difficult to make.

Stephen

[rocco]

Stephen what is a heater warning plate?

You can see it on my engine here. I took the photo on collection day so no comments about cleanliness are necessary!

MoggyEngineHeaterWarning.jpg

Thank you. Does the warning sign/plate/badge have a backing plate or are the clips riveted directly to the badge? Terry clips and a badge are easy enough to buy but if there’s a backing plate that would be tricky to find although not difficult to make.

Stephen

It's got a couple of clips riveted to the backside of it that just pop over the pipe. It's been in the ultrasonic cleaner along with the pipe and plenty of other parts and look pretty good now.